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    Hi there that sounds alright but what do you think of tribulus do you recon that is good for boosting your testosterone

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    Wow this is ALOT to sink in! I am trying though!

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    Delta sleep-inducing peptide

    Delta sleep-inducing peptide, abbreviated DSIP, is a neuropeptide that when infused into the mesodiencephalic ventricle of recipient rabbits induces spindle and delta EEG activity and reduced motor activities.[1]

    Its aminoacid sequence is trp-ala-Gly-Gly-Asp-Ala-Ser-Gly-Glu. However, it is the only neuropeptide in history whose gene is unknown, raising serious questions regarding the actual existence of this peptide in nature.


    Delta sleep-inducing peptide was first discovered in 1974 by the Swiss Schoenenberger-Monnier group who isolated it from the cerebral venous blood of rabbits in an induced state of sleep. It was primarily believed to be involved in sleep regulation due to its apparent ability to induce slow-wave sleep in rabbits, but studies on the subject have been contradictory.[2]

    Delta-sleep-inducing peptide (DSIP)-like material has been found in human breast milk.[3]

    Structure and Interactions

    DSIP is an amphiphilic peptide of molecular weight 850 daltons with the amino acid motif:

    It has been found in both free and bound forms in the hypothalamus, limbic system and pituitary as well as various peripheral organs, tissues and body fluids.[5] In the pituitary it co-localises with many peptide and non-peptide mediators such as corticotropin-like intermediate peptide (CLIP), adrenocorticotrophic hormone (ACTH), melanocyte-stimulating hormone (MSH), thyroid-stimulating hormone (TSH) and melanin concentrating hormone (MCH). It is abundant in the gut secretory cells and in the pancreas where it co-localises with glucagon.[4]

    In the brain its action may be mediated by NMDA receptors.[6] In another study Delta sleep-inducing peptide stimulated Acetyltransferase activity through ***945;1 receptors in rats.[7] It is unknown where DSIP is synthesized.

    In vitro it has been found to have a low molecular stability with a half life of only 15 minutes due to the action of a specific aminopeptidase-like enzyme.[8] It has been suggested that in the body it complexes with carrier proteins to prevent degradation, or exists as a component of a large precursor molecule,[9] but as yet no structure or gene has been found for this precursor.

    Evidence supports the current belief that it is regulated by glucocorticoids.[10]

    Gimble et al. suggest that DSIP interacts with components of the MAPK cascade and is homologous to glucocorticoid-induced leucine zipper (GILZ).[11] GILZ can be induced by Dexamethasone. It prevents Raf-1 activation, which inhibits phosphorylation and activation of ERK.[12]


    Many roles for DSIP have been suggested following research carried out using peptide analogues with a greater molecular stability [13] and through measuring DSIP-like immunological (DSIP-LI) response by injecting DSIP antiserum and antibodies.[14]

    Roles in endocrine regulation

    Decreases basal corticotropin level and blocks its release.[8]
    Stimulates release of luteinizing hormone (LH).[15]
    Stimulates release of somatoliberin and somatotrophin secretion and inhibits somatostatin secretion.[16]

    Roles in physiological processes

    Can act as a stress limiting factor.[17][18][19]

    May have a direct or indirect effect on body temperature and alleviating hypothermia.[20][21][22]

    Can normalize blood pressure and myocardial contraction.[8][23]

    It has been shown to enhance the efficiency of oxidative phosphorylation in rat mitochondria in vitro, suggesting it may have antioxidant effects.[19]

    There is also conflicting evidence as to its involvement in sleep patterns. Some studies suggest a link between DSIP and slow-wave sleep (SWS) promotion[24][25] and suppression of paradoxical sleep, (PS)[26][27] while some studies show no correlation.[28] Stronger effects on sleep have been noted for the synthesized analogues of DSIP.[29]

    It may have an impact on human lens epithelial cell function via the MAPK pathway, which is involved in cell proliferation, differentiation, motility, survival, and apoptosis.[12]

    Roles in Disease and Medicine

    It has been found to have anticarcinogenic properties. In a study on mice, injecting a preparation of DSIP over the mice's lifetime decreased total spontaneous tumor incidence 2.6-fold.[30]

    The same study found it to also have geroprotective effects: it slowed down the age-related switching-off of oestrous function; it decreased by 22.6% the frequency of chromosome aberrations in bone marrow cells and it increased by 24.1% maximum life span in comparison with the control group.

    Levels of DSIP may be significant in patients diagnosed with major depressive disorder (MDD). In several studies, levels of DSIP in the plasma and cerebrospinal fluid are significantly deviated from the norm in patients with MDD, though there are contradictions as to whether levels are higher or lower than healthy control patients.[10][31][32]

    Studies have demonstrated a direct link between GILZ expression (homologous to DSIP) and adipogenesis which has links to obesity and metabolic syndrome.[33]

    In studies on rats with metaphit-induced epilepsy DSIP acted as an anticonvulsant, significantly decreasing the incidence and duration of fits suggesting DSIP as a potential treatment for epilepsy.[34][35]

    DSIP has been found to have an analgesic effect. In studies on mice it was found to have a potent antinociceptive effect when administered intracerebroventricularly or intracisternally (see: Route of administration).[36]

    Due to its possible effects on sleep and nociception, trials have been carried out to determine whether DSIP can be used as an anaesthetic. One such study found that administration of DSIP to humans as an adjunct to isoflurane anaesthesia actually increased the heart rate and reduced the depth of anaesthesia instead of deepening it as expected.[37]

    Low plasma concentrations of DSIP have been found in patients with Cushing's syndrome.[38]

    In Alzheimer's patients levels of DSIP have been found to be slightly elevated, though this is unlikely to be causal.[39]

    A preparation of DSIP, Deltaran, has been used to correct central nervous system function in children after antiblastomic therapy. Ten children aged 3?16 years were given a ten-day course of Deltaran and their bioelectric activity recorded. It was found that the chemotherapy-induced impairment in the bioelectrical activity of 9 out of the 10 children was reduced by administration of DSIP.[40]

    DSIP can act antagonistically on opiate receptors to significantly inhibit the development of opioid and alcohol dependence and is currently being used in clinical trials to treat withdrawal syndrome.[41][42] In one such trial it was reported that in 97% of opiate-dependent and 87% of alcohol-dependent patients the symptoms were alleviated by DSIP administration.[43]

    In some studies administration of DSIP has alleviated narcolepsy and normalized disturbed sleeping patterns.[44][45]
    Safety and possible side-effects of long-term DSIP use hasn't been established in clinical research studies.


    1^ Monnier M, Dudler L, G?chter R, Maier PF, Tobler HJ, Schoenenberger GA (April 1977). "The delta sleep inducing peptide (DSIP). Comparative properties of the original and synthetic nonapeptide". Experientia 33 (4): 548?52. doi:10.1007/BF01922266. PMID 862769.

    2^ Schoenenberger GA, Maier PF, Tobler HJ and Monnier M (1977). "A naturally occurring delta-EEG enhancing nonapeptide in rabbits". European Journal of Physiology 369 (2): 99?109. doi:10.1007/BF00591565. PMID 560681.

    3^ Graf MV, Hunter CA, Kastin AJ (1984). "Presence of Delta-Sleep-Inducing Peptide-Like Material in Human Milk". Journal of Clinical Endocrinology & Metabolism 59 (1): 127?32. doi:10.1210/jcem-59-1-127. PMID 6547144.

    4^ a b Kovalzon VM and Strekalova TV (2006). "Delta sleep-inducing peptide (DSIP): a still unresolved riddle". Journal of Neurochemistry 97 (2): 303?309. doi:10.1111/j.1471-4159.2006.03693.x. PMID 16539679.

    5^ Charnay Y, Bouras C, Vallet PG, Golaz J, Guntern R, Constantinidis J (1989). "Immunohistochemical distribution of delta sleep inducing peptide in the rabbit brain and hypophysis". Neuroendocrinology 49 (2): 169?175. doi:10.1159/000125110. PMID 2657475.

    6^ Sudakova KV, Umriukhina PE, Rayevskyb KS (2004). "Delta-sleep inducing peptide and neuronal activity after glutamate microiontophoresis: the role of NMDA-receptors". Pathophysiology 11 (2): 81?86. doi:10.1016/j.pathophys.2004.03.003. PMID 15364118.

    7^ Graf MV, Schoenenberger, GA (1987). "Delta Sleep-Inducing Peptide Modulates the Stimulation of Rat Pineal N-Acetyltransferase Activity by Involving the ***945;1-Adrenergic Receptor". Journal of Neurochemistry 48 (4): 1252?1257. doi:10.1111/j.1471-4159.1987.tb05654.x. PMID 3029331.

    8^ a b c Schoenenberger GA (1984). "Characterization, properties and multivariate functions of Delta-Sleep Inducing Peptide (DSIP)". European Neurology 23 (5): 321?345. doi:10.1159/000115711. PMID 6548966.

    9^ Inou? S and Borbely AA, ed. (1985). Endogenous Sleep Substances And Sleep Regulation: Proceedings of the Taniguchi Symposia on Brain Sciences. Boston: Brill Academic Publishers. ISBN 90-6764-058-1.

    10^ a b Westrin A, Ekman R, and Traskman-Bendz L (1998). "High Delta Sleep-Inducing Peptide-Like Immunoreactivity in Plasma in Suicidal Patients with Major Depressive Disorder". Biological Psychiatry 43 (10): 734?739. doi:10.1016/S0006-3223(97)00254-0. PMID 9606527.

    11^ Gimble JM, Ptitsyn AA, Goh BC, Hebert T, Yu G, Wu X, Zvonic S, Shi X-M and Floyd ZE (2009). "Delta sleep-inducing peptide and glucocorticoidinduced leucine zipper: potential links between circadian mechanisms and obesity?". Obesity reviews 10: 46?51. doi:10.1111/j.1467-789X.2009.00661.x. PMID 19849801.

    12^ a b Gupta V, Awasthi N and Wagner BJ (2007). "Specific Activation of the Glucocorticoid Receptor and Modulation of Signal Transduction Pathways in Human Lens Epithelial Cells". Investigative Ophthalmology and Visual Science 48 (4): 1724?1734. doi:10.1167/iovs.06-0889. PMC 2814520. PMID 17389505.

    13^ synthesized by V. N. Kalikhevich and S. I. Churkina, University Chemical Institute, St. Petersburg, Russia, and I. I. Mikhaleva and I. A. Prudchenko, Institute of Bio-organic Chemistry, Russian Academy of Sciences, Moscow

    14^ Charnay Y, Golaz J, Vallet PG, Bouras C (1992). "Production and immunohistochemical application of monoclonal antibodies against delta sleep-inducing peptide". J Chem Neuroanat 5 (6): 503?9. doi:10.1016/0891-0618(92)90005-B. PMID 1476667.

    15^ Iyer KS and McCann SM (1987). "Delta sleep inducing peptide (DSIP) stimulates the release of LH but not FSH via a hypothalamic site of action in the rat". Brain Research Bulletin 15 (5): 535?538. doi:10.1016/0361-9230(87)90069-4. PMID 3121137.

    16^ Koval'zon VM (1994). "[DSIP: the sleep peptide or an unknown hypothalamic hormone?]" (in Russian). Zh. Evol. Biokhim. Fiziol. 30 (2): 310?9. PMID 7817664.: Kovalzon VM (1994). "DSIP: a sleep peptide or unknown hypothalamic hormone?". J. Evol. Biochem. Physiol. 30: 195?199.

    17^ Kitayama I, Kawguchi S Murase S, Otani M, Takayama M, Nakamura T Komoiri T Nomura, Natotani N, Fuse K (1992). "Noradrenergic and neuroendocrine function in chronic walking stress-induced model of depression in rats". In Kvet***328;ansk? R, McCarty R, Axelrod J. Stress: Neuroendocrine and Molecular Approaches. Boca Raton: CRC Press. pp. 59?72. ISBN 2-88124-506-4.

    18^ Sudakova KV, Coghlan JP, Kotov AV, Salieva RM, Polyntsev YV, Koplik EV (1995). "Delta-sleep inducing peptide sequels in mechanisms of resistance to emotional stress". Ann. N.Y. Acad. Sci. 771: 240?251. doi:10.1111/j.1749-6632.1995.tb44685.x. PMID 8597403.

    19^ a b Khvatova EM, Samartzev VN, Zagoskin PP, Prudchenko IA, Mikhaleva II (2003). "Delta sleep inducing peptide (DSIP): effect on respiration activity in rat brain mitochondria and stress protective potency under experimental hypoxia". Peptides 24 (2): 307?311. doi:10.1016/S0196-9781(03)00040-8. PMID 12668217.

    20^ Pollard BJ and Pomfrett CJD (2001). "Delta sleep-inducing peptide". Eur. J. Anaesthesiol. 18 (7): 419?422. PMID 11437870.

    21^ Yehuda S, Kastin AJ and Coy DH (1980). "Thermoragulatory and locomotor effects of DSIP: paradoxical interaction with d-amphetamine". Pharmacol. Biochem. Behav. 13 (6): 895?900. doi:10.1016/0091-3057(80)90225-7. PMID 6894196.

    22^ Yehuda S and Mostofsky DI (1984). "Modification of the hypothermic circadian cycles induced by DSIP and melatonin in pinealectomized and hypophysectomised rats". Peptides 5 (3): 495?497. doi:10.1016/0196-9781(84)90076-7. PMID 6548024.

    23^ Yehuda S, Carasso RL (February 1988). "DSIP--a tool for investigating the sleep onset mechanism: a review". Int. J. Neurosci. 38 (3-4): 345?53. doi:10.3109/00207458808990695. PMID 3286557.

    24^ Iyer KS, Marks GA, Kastin AJ, and McCann SM (1988). "Evidence for a role of delta sleep-inducing peptide in slow-wave sleep and sleep-related growth hormone release in the rat". Proc Natl Acad Sci U S A 85 (10): 3653?3656. doi:10.1073/pnas.85.10.3653. PMC 280272. PMID 3368469.

    25^ Susi***263; V, Masirevi***263; G, Toti***263; S (1987). "The effects of delta-sleep-inducing peptide (DSIP) on wakefulness and sleep patterns in the cat". Brain Research 414 (2): 262?70. doi:10.1016/0006-8993(87)90006-0. PMID 3620931.

    26^ Seifritz E, Muller M, Schonenberger G, Trachsel L, Hemmeter U, Hatzinger M, Ernst A, Moore P and Holsboer-Trachsler E (1995). "Human plasma DSIP decreases at the initiation of sleep at different circadian times". Peptides 16 (8): 1475?1481. doi:10.1016/0196-9781(95)02027-6. PMID 8745061.

    27^ Steiger A and Holsboer F (1997). "Neuropeptides and human sleep". Sleep 20 (11): 1038?1052. PMID 9456470.

    28^ Nakagaki K, Ebihara S, Usui S, Honda Y, Takahashi Y, Kato N (1986). "Effects of intraventricular injection of anti-DSIP serum on sleep in rats". Yakubutsu Seishin Kodo (Japanese journal of psychopharmacology) 6: 259?65.

    29^ Kovalzon VM (2001). "Sleep-Inducing Properties of DSIP Analogs: Structural and Functional Relationships". Biology Bulletin 28: 394?400. doi:10.1023/A:1016679208936.

    30^ Popovich IG, Voitenkov BO, Anisimov VN, Ivanov VT, Mikhaleva II, Zabezhinski MA, Alimova IN, Baturin DA, Zavarzina NY, Rosenfeld SV, Semenchenko AV, Yashin Aromatase inhibitor (AI) (2003). "Effect of delta-sleep inducing peptide-containing preparation Deltaran on biomarkers of aging, life span and spontaneous tumor incidence in female SHR mice". Mechanisms of Ageing and Development 124 (6): 721?731. doi:10.1016/S0047-6374(03)00082-4. PMID 12782416.

    31^ Walleus H, Widerl?v E and Ekman R (1985). "Decreased concentrations of delta-sleep inducing peptide in plasma and cerebrospinal fluid from depressed patients". Nordic Journal of Psychiatry 39: 63?67. doi:10.3109/08039488509101959.

    32^ Bjartell A, Ekman R, Sundler F and Widerl?v E (1988). "Delta sleep-inducing peptide (DSIP): An overview of central actions and possible relationship to psychiatric illnesses". Nordic Journal of Psychiatry 42: 111?117. doi:10.3109/08039488809103215.

    33^ Shi X, Shi W, Li Q, Song B, Wan M, Bai S (2003). "A glucocorticoid-induced leucine-zipper protein, GILZ, inhibits adipogenesis of mesenchymal cells". EMBO Rep 4 (4): 374?380. doi:10.1038/sj.embor.embor805. PMC 1319161. PMID 12671681.

    34^ Stanojilovic OP, Zivanovic DP and Su Sic VT (2002). "The effects of Delta Sleep-Inducing Peptide on incidence and severity in metaphit-induced epilepsy in rats". Pharmacological Research 45 (3): 241?247. doi:10.1006/phrs.2001.0938. PMID 11884222.

    35^ Stanojlovi***263; O, Zivanovi***263; D, Mirkovi***263; S, Mikhaleva I (February 2004). "Delta sleep-inducing peptide and its tetrapeptide analogue alleviate severity of metaphit seizures". Pharmacol. Biochem. Behav. 77 (2): 227?34. doi:10.1016/j.pbb.2003.10.014. PMID 14751449.

    36^ Nakamura A, Nakashima M, Sugao T, Kanemoto H, Fukumura Y, Shiomi H (1988). "Potent antinociceptive effect of centrally administered delta-sleep-inducing peptide (DSIP)". Eur J Pharmacol 155 (3): 247?53. doi:10.1016/0014-2999(88)90510-9. PMID 2853064.

    37^ Pomfrett CJD, Dolling S, Anders NRK, Glover DG, Bryan A, Pollard BJ (2009). "Delta sleep-inducing peptide alters bispectral index, the electroencephalogram and heart rate variability when used as an adjunct to isoflurane anaesthesia". Eur J Anaesthesiol 26 (2): 128?34. doi:10.1097/EJA.0b013e32831c8644. PMID 19142086.

    38^ Friedman TC, Garc?a-Borreguero D, Hardwick D, Akuete CN, Doppman JL, Dorn LD, Barker CN, Yanovski JA, Chrousos GP (December 1994). "Decreased delta-sleep and plasma delta-sleep-inducing peptide in patients with Cushing syndrome". Neuroendocrinology 60 (6): 626?34. doi:10.1159/000126806. PMID 7700506.

    39^ Torreilles F and Touchon J (2002). "Pathogenic theories and intrathecal analysis of the sporadic form of Alzheimer's disease". Progress in Neurobiology 66 (3): 191?203. doi:10.1016/S0301-0082(01)00030-2. PMID 11943451.

    40^ Sinyukhin AB, Timoshinov GP, Komilov VA, Shabanov PD (2009). "Delta sleep-inducing peptide analogue corrects the eNS functional state of children treated with antiblastomic therapy". European Neuropsychopharmacology 19: S681. doi:10.1016/S0924-977X(09)71101-0.

    41^ Soyka M and Rothenhaeusler H (1997). "Delta Sleep-Inducing Peptide Opioid Detoxi***64257;cation". Am. J. Psychiat. 154 (5): 714?715. PMID 9137140.

    42^ Yukhananov RY, Tennila TML, Miroshnichenko II, Kudrina VS, Ushakov AN and Melnik EI (1992). "Ethanol and Delta Sleep Inducing Peptide effects on brain monoamines". Pharmacol. Bio-chem. Behav. 43: 683?687. doi:10.1016/0091-3057(92)90396-W.

    43^ Backmund M, Meyer K, Rothenhaeusler HB and Soyka M (1998). "Opioid detoxi***64257;cation with delta sleep-inducing peptide: results of an open clinical trial.". J. Clin. Psychopharmacol. 18 (3): 257?258. doi:10.1097/00004714-199806000-00016. PMID 9617990.

    44^ Schneider-Helmert D (1986). "DSIP in Sleep Disturbances". Eur Neurol 25: 154?157. doi:10.1159/000116097. PMID 3758119.

    45^ Schneider-Helmert D and Schoenenberger GA (1981). "The influence of synthetic DSIP (delta-sleep-inducing-peptide) on disturbed human sleep". Cellular and Molecular Life Sciences 37: 913?917. doi:10.1007/BF01971753

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  4. #54
    CHEMICALLY ENGINEERED vibrant's Avatar
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    more on DSIP:

    European Journal of Anaesthesiology:
    July 2001 - Volume 18 - Issue 7 - pp 419-422
    Delta sleep-inducing peptide
    Pollard, B. J.; Pomfrett, C. J. D.

    Delta sleep-inducing peptide (DSIP) is a naturally occurring substance, which was originally isolated from rabbit brain in 1977 [1]. This curious substance is a nonapeptide that is normally synthesized in the hypothalamus and targets multiple sites including some within the brainstem [2]. As its name suggests DSIP promotes sleep and this has been demonstrated in rabbits, mice, rats, cats and human beings [3-5]. In fact DSIP promotes a particular type of sleep which is characterized by an increase in the delta rhythm of the EEG.

    DSIP is normally present in minute amounts in the blood. Brain and plasma DSIP concentrations exhibit a marked diurnal variation [6] and there has been shown to be a correlation between DSIP plasma concentrations and circadian rhythm in human beings. Concentrations are low in the mornings and higher in the afternoons. An elevation of endogenous DSIP concentration has been shown to be associated with suppression of both slow-wave sleep and rapid-eye-movement sleep and interestingly also with body temperature [7]. Plasma concentrations of DSIP are influenced by the initiation of sleep [8]. Patients with Cushing's syndrome suffer from a lack of slow-wave sleep but the diurnal variation in slow-wave and rapid-eye-movement sleep in those patients appears to be similar to that in normal patients [9].

    When compared with most other peptides, DSIP is unusual in that it can freely cross the blood-brain barrier and is readily absorbed from the gut without being denatured by enzymes [10,11]. DSIP is present in relatively high concentrations in human milk (10-30 ng mL-1). Any mother who has breast-fed her babies will attest to the ability of a feed to induce sleep. However, a feed of artificial milk may have a similar effect, and it is not known whether DSIP concentrations are related to the sleep-wake cycle in human neonates [12].

    DSIP has been synthesized. Administration of the synthetic substance does not induce tolerance [13]. DSIP can be assayed by several techniques including radioimmunoassay (RIA), enzyme immunoassay and high-performance liquid chromatography with RIA [14-16]. DSIP has a half-life in human plasma of between 7 and 8 min [2]. It is degraded in blood, the pathway involving the amino-peptidases [17]. A potential drug interaction might therefore be envisaged between DSIP and drugs which inhibit or are themselves metabolized by peptidases. Captopril is one such agent and patients currently undergoing treatment with any of the angiotensin-converting enzyme inhibitors should probably be excluded from any DSIP treatment protocol until further studies have been undertaken.

    DSIP and sleep
    The innate controlling mechanisms of sleep have fascinated scientists for generations and many different endogenous compounds have been proposed as controllers of sleep over the years. These include cholecystokinin, prostaglandin I2 and various unknown substances labelled 'sleep-promoting substances'. Indeed, the majority of humoral mediators seem to have some relation to sleep by, for example, affecting circadian rhythms or arousal states. In some cases, however, it is not clear if the humoral mediator is driving the sleep pattern or responding to the sleep pattern.

    Since the discovery of DSIP a number of studies have been undertaken to test the hypothesis that DSIP may be the principal endogenous sleep factor. It is reported to increase the 'pressure to sleep' in human subjects who have been injected with small doses and this, together with its ability to induce delta-wave sleep, led to its consideration as a treatment for insomnia. A number of studies have examined this use with varied success [18-21].

    DSIP has been described as a sleep-promoting substance rather than a sedative. There is a modulating effect on sleep and wake functions with a greater activity in circumstances where sleep is disturbed. There are minimal effects in healthy subjects who are not suffering from sleep disturbance [22]. DSIP is not a night sedation drug which needs to be given just before retiring. A dose of DSIP given during the course of the day will promote improved sleep on the next night and for several nights thereafter. Despite these clear short-term benefits, however, doubt has been cast on whether or not DSIP treatment will prove to be of major benefit in long-term management of insomnia.

    Studies have been undertaken in patients suffering from the sleep apnoea syndrome and from narcolepsy. Unfortunately, no difference in DSIP concentrations has been found between those patients and normal patients [23]. DSIP may, paradoxically, be of use in the treatment of narcolepsy and it is possible that it exerts its effect by restoring circadian rhythms [24]. When single and multiple injections of DSIP were given in a controlled double-blind study, disturbed sleep was normalized and better performance and increased alertness was seen during awake cycles together with improved stress tolerance and coping behaviour [22].

    Non-sleep effects
    DSIP has been shown to have an anticonvulsant action in the rat. The threshold to NMDA- and picrotoxin-induced convulsions is increased by DSIP [25,26]. This anticonvulsant effect may undergo a diurnal variation with greater antiepileptic activity seen at night [27]. DSIP is not unique in possessing a diurnal variation in anticonvulsant activity as melatonin, b-endorphin and dexamphetamine all reduce seizure threshold during the day and it is possible that DSIP simply represents one of the endogenous controls of brain excitability [28]. DSIP has an antinociceptive action in mice, an effect which is blocked by naloxone [29].

    A neuroprotective effect has been demonstrated in rats subjected to bilateral carotid ligation [30]. A reduced mortality was observed together with a reduction in postischaemia function. DSIP also reduced brain swelling in a model of toxic cerebral oedema in the rat [31].

    DSIP attenuates emotional and psychological responses to stress and also reduces the central amine responses to stress in rats [32]. The action of corticotrophin releasing factor on the pituitary gland in the rat is attenuated with a consequential inhibition of pituitary adrenocorticotrophic hormone (ACTH) secretion [33]. The situation is less clear in man as although one study confirmed this finding [34] another reported no inhibitory effect on the adrenocortical axis to both physiological and stressor stimuli [35]. DSIP had no effect on growth hormone or prolactin concentrations when administered to human volunteers [36]. In one study, infusions of 3 or 4 mg (an enormous dose) had no effect on ACTH levels or on cortisol secretion [35] although in another study DSIP 25 nmol kg-1 significantly decreased ACTH concentrations [36].

    DSIP concentrations change during certain psychiatric disorders. Patients suffering from schizophrenia and depression have lower plasma and cerebrospinal fluid concentrations of DSIP than comparable normal volunteers [37]. Concentrations were also inversely correlated with sleep disturbance in those patients.

    As might be expected of any substance which is naturally occurring, side-effects are uncommon. Normally, concentrations would be very low and therefore the injection of large, probably non-physiological doses might be expected to at least produce some unwanted effect. No significant side-effects have so far been reported with DSIP. In some human studies, transient headache, nausea and vertigo have been reported. DSIP actually appears to be incredibly safe as its LD50 has never been determined because it has never so far proved possible to kill an animal whatever the dose of DSIP administered.

    Clinical uses
    Clinical uses for DSIP already exist. The agent has been used for the treatment of alcohol and opioid withdrawal with some success [38]. Clinical symptoms and signs disappear after injection of DSIP although some patients have reported occasional headaches.

    DSIP possesses a number of other apparently unrelated properties. In hypertensive rats, 200 ***956;g kg-1 day-1of DSIP for 10 days had an antihypertensive effect [39]. DSIP has also been reported to possess antimetastatic activity [40]. It may also reduce amphetamine-induced hyperthermia and may be beneficial in some chronic pain conditions [41].

    An interesting study reported in 1986 injected DSIP and several analogues of the peptide directly into the cerebral ventricle of rats. DSIP did not increase sleep and this was thought to be due to its very rapid metabolism. However, two of the analogues did induce sleep but one produced arousal. It would appear therefore that there might be the potential for not only sleep but sleep reversal within the analogues of DSIP [42].

    The molecular sites for the action of anaesthetic agents are being identified. Volatile agents appear to act on specific sites of the GABA-A and glycine receptors, whereas ketamine and xenon act on the NMDA receptors. These sites are reproducible and clearly defined, but what is their natural purpose, as neither volatile anaesthetic agents nor xenon are usually found in physiological systems? It is possible, but has yet to be demonstrated, that DSIP and other neuroactive peptides selectively bind to these regions of GABA-A, glycine and/or NMDA receptors.

    Is DSIP of relevance to the anaesthesiologist?
    Anaesthesia is physiologically distinct from natural sleep and anaesthetic agents appear to work on receptor mechanisms normally dedicated to the control of brain metabolism. Conventional sleep staging does not indicate the depth of anaesthesia; rapid-eye movements (REM) and other characteristics of natural sleep are not seen during anaesthesia. It is possible, however, that anaesthesia is mimicking a natural phenomenon such as hibernation by copying the action of natural neuroactive peptides such as DSIP.

    What is the significance of DSIP to anaesthesia? Could DSIP be the body's natural anaesthetic? Is activation of the DSIP receptors related to the state of anaesthesia? These questions must remain speculative for the present. Whether or not DSIP is the body's natural anaesthetic, or a substance closely involved in this process, it may not prove to be possible to administer it in a way which could be regarded as anaesthesia. Could it therefore be used as the body's natural sedative? No studies have been performed to investigate this possible use although it would theoretically seem to have potential.

    Source: Delta sleep-inducing peptide : European Journal of Anaesthesiology (EJA)

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    Holy crap that was a lot of reading! Great info it was totally worth it

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    Great info it was totally worth it, Wow, I never knew about this kind of peptides overview before. That's pretty interesting Thanks for sharing this information.

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    Great peptide information

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